Question

Why does van der waal forces increase down group 7?

Answer 1

The van der Waals forces increases since the atoms have more electrons as you descend the group.

Van Der Waal forces are the forces that are generated due to temporary charges that are formed around the atom due to movement of electrons.

The speed of the electrons revolving in the outermost shell is slow for large atoms and fast for small atoms. Slower the revolution of electrons in the shell more is the possibility of forming a temporary dipole and more the Van Der Waal bonding.

So as we move down the group size of atom increases do does the van der waal forces.

Hope this helps.